The human foot consists of numerous different bones. These bones, in conjunction with numerous muscles and ligaments, distribute the body's weight on the ground. For each foot, there is a neutral alignment position. In this position, the various bones are aligned properly, and the various muscles and ligaments are not unnecessarily tensioned. However, for some feet in the neutral alignment position, the bottoms thereof are not horizontal. Moreover, the toe and heel might not be coplanar. When moving about, as by running or walking, on an uneven surface, this is of little consequence. To accommodate the variations in the surface, each foot is randomly deflected by small amounts. As a consequence, the various muscles and tendons are more or less uniformly stretched.
However, for many people, most everyday movement is carried out on a substantially flat surface. Thus, for people living in an urban environment, nearly all surfaces on which they walk are horizontal with little unevenness. Also, for athletes, many playing or exercise surfaces are also horizontal. As a result, if a foot has a non-horizontal neutral alignment position, then when weight is placed on the foot it has to adopt a "compensated" position. In other words, the foot compensates, so that its bottom surface is horizontal. In the compensated position, ligaments can be stressed and imbalances set up in various muscles, the degree of stress and muscle imbalances being proportional to the degree of compensation. This can also effect the amount of flexibility.
It has also been realized that maintaining proper neutral alignment of the feet is important, since the various components of the human skeleton are related, and stress set up in one part of the skeleton can effect numerous other parts. Thus, the continuous maintenance of the feet in compensated positions can lead to stress and problems in not only the feet themselves, but also in the legs, knees, lower and upper back and neck.
For athletes, a large number of injuries are caused by stress from over-use or due to a limited amount of flexibility. It is believed that by stabilizing the feet into neutral alignment positions and reconditioning the body to a balance of strength and flexibility, greater endurance can be achieved.
Accordingly, it is desirable to obtain neutral alignment in a person's foot. However, the problem arises of accurately determining the neutral alignment position of the foot. Present techniques are somewhat crude and ineffective.
In one technique, a goniometer or tractograph is used. The foot is placed in a non-weight bearing position, and palpitated to align the bones. To a large extent, the measurements rely upon the judgment of the person taking the measurements. Moreover, such measurements are determined from simple visual observation.
Other techniques take measurements in a weight bearing condition by the taking of an imprint of the foot. However, these measuring techniques do not permit free, unrestricted movement of the foot in all three planes which is a particularly important factor in the accurate determination of the neutral alignment position. Furthermore, these rudimentary measurements become the basis for the preparation of an orthotic which compensates the foot by allowing for separate misalignment of the heel and the toe. However, due to the inaccuracies in the current measuring processes, many orthotics still result in residual misalignment of the foot.
It has been realized that it is desirable to achieve an accurate measurement of the neutral alignment position of the foot. Such a measurement should not rely excessively upon the judgment or experience of the person taking the measurements. Further, to achieve accurate measurements of the neutral alignment position, these measurements should be taken in a load or weight bearing position, with the foot free to move in certain directions.
It is therefore an object of the present invention to obviate or mitigate the above-mentioned disadvantages by providing a novel technique of measuring the neutral alignment position.
In accordance with the present invention, there is provided an apparatus for determining the neutral alignment position of the toe, arch and heel portions of the foot, comprising:
a toe portion support means, PA0 an arch portion support means, PA0 a heel portion support means, PA0 displacement means coupled with each of the support means to displace vertically one of the support means in response to vertical displacement of another of the support means. PA0 aligning the toe, arch and heel portions of a foot on the respective support means, PA0 orienting the person so as to place said foot in a body weight bearing condition, so as to apply a pressure distribution over said support means, said pressure distribution causing said foot to assume a neutral alignment position by way of relative displacements of said support means with respect to said vertical axis, and rotations of said support means with respect to said longitudinal axis, and PA0 observing the results of said displacements and rotations, so as to determine said neutral alignment position PA0 placing the feet of said user on respective ones of two assemblies, each of said assemblies comprising a toe support, an arch support and a heel support respectively, said supports in each assembly being disposed along a longitudinal axis and displaceable with respect to a vertical axis, rotatable about a longitudinal axis and collectively rotatable about said vertical axis, PA0 orienting said person to a position wherein said feet are in a body weight bearing condition, causing a pressure distributions to be applied over said supports, PA0 said pressure distribution causing relative vertical displacement between said supports to balance said pressure distribution for each foot, said vertical displacement being governed by a relationship between said supports, whereby displacement of one of said supports causes a compensating displacement of at least one of said other supports, PA0 said pressure distribution also causing rotation of at least said heel and toe supports about said longitudinal axis to balance said pressure distribution over the respective support, and the collective rotation of said supports in at least one of said assemblies about a vertical axis so as to accommodate torsional imbalances between the foot, the leg and the hip portion of said person, PA0 said vertical displacements supports causing each of said feet to assume a neutral alignment position, PA0 causing vertical displacements of said toe, arch and heel portions from said neutral alignment position toward displacement limits in each direction therefrom, PA0 measuring said displacements so as to determine said displacement limits, PA0 causing rotation about said longitudinal axis of said toe, arch and heel portions from said neutral alignment position toward limits of longitudinal rotation in each sense therefrom, PA0 measuring said rotations so as to determine said limits of rotation, PA0 causing collective rotation of said supports for at least one of said feet from said neutral alignment position toward limits of collective rotation about said vertical axis in each sense therefrom, PA0 measuring said collective rotations so as to determine said collective rotation limits, PA0 said limits of displacement and rotation being indicative of ranges of motion in each of three dimensions.
each of the support means being mounted along a longitudinal axis to be aligned with the elongate dimension of the foot, so as to be engageable with the respective portions thereof, each of the support means being movable along a vertical axis and rotatable about at least the longitudinal axis, and
A method is also provided for determining the neutral alignment position of the foot of a person using a device comprising a toe portion support means, an arch portion support means, a heel portion support means, each of said support means being mounted along a longitudinal axis to be aligned with the elongate dimension of said foot so as to be engageable with the respective portions thereof, each of said support means being movable along a vertical axis and rotatable about at least said longitudinal axis, and displacement means coupled with each of said support means to displace vertically one of said support means in response to vertical displacement of another of said support means,
A further method is provided for ascertaining the kinesic condition of a person comprising the steps of:
Thus, the present invention involves the measurement of the neutral alignment position while the foot is in a load bearing position, and thereby provides a more accurate determination of the neutral alignment position than those devices presently known. Furthermore, the present invention enables the analysis of the bone alignment as well as muscle and ligament imbalance by providing a technique for determining ranges of motion of the various portions of the foot as well as the leg and hips.
The term "neutral alignment position" refers to an equilibrium position of the foot in a weight bearing condition in which the bones are aligned and the muscles and ligaments are balanced. This position is identifiable in any body configuration, wherein each foot assumes a particular position depending on the body weight exerted on the foot and the shape of the ground surface, and in such a position cooperates with the bones, muscles and ligaments in the rest of the body to provide the most efficient use of energy in transferring forces to the ground.